Spacecraft systems, which include earth and planetary orbiting satellites and deep space probes, often incorporate deployable systems including; Deployable structures, deployable solar arrays, deployable antennas, and other deployable subsystems. These deployable systems must be configurable between a storage configuration that enables the entire spacecraft system, inclusive of the deployable structure, to fit within the small volume constraints of a launch vehicle, and a deployed operable configuration that enables the spacecraft to function in a desired manner once in space.
Once the spacecraft is in space, the spacecraft is typically configured for use by deploying an assembly of extendable deployable components. For example, the assembly of extendable components may comprise an extended solar panel or blanket array that is used to convert collected solar radiation into electrical energy. In another example, the assembly of extendable components may comprise an extendable antenna assembly that is used to transmit and receive electromagnetic signals to and from a plurality of earth-based installations. In yet another example, the assembly of extendable components may comprise an extendable boom assembly that is used as a platform for a critical sensor, such as a magnetometer or electric field sensor.
The deployable boom assemblies are required to compactly stow into a small volume and then reliably deploy in a known kinematic manner to form a rigid and strong appendage. The boom assemblies must also be lightweight so they can be launched into space, and low cost so they can be affordable to the program. As increasingly advanced types of spacecraft are being developed, it has become apparent that currently boom technologies are insufficient for meeting emerging applications. In particular, current boom assemblies are not scalable to very long lengths and this limits a spacecraft's capability, particularly for emerging missions that demand a much longer boom length to provide much higher power production from a solar array, or a much broader aperture for an antenna.
Typical state-of-the-practice continuous-piece construction booms range from 2 meters to 10 meters in length. Continuous length booms of very long lengths are extremely difficult to manufacture using current state-of-the-practice technologies due to fabrication, material and facility limitations. For applications much longer than 10 meters in length articulated booms structures are commonly used. Articulating booms structures are typically comprised of multiple and complex articulated deploying elements that can be integrated in a repetitive manner to form a desired boom length. The articulated boom technology is high cost, high mass, and labor intensive to manufacture.
To minimize mass, maximize strength and stiffness, enable future missions, and significantly reduce cost there is a need for simple, near continuous piece construction, boom assemblies that can be scaled from 2 meters in length to literally hundreds of meters in length. Moreover, since cost and reliability are major considerations in the design of spacecraft system, it is imperative for the boom assembly to have a simple, reliable design so as to reduce the manufacturing costs of the boom assembly.
Hence, there is a continuing need for extendable boom assemblies for spacecraft that are lightweight and are readily stowable into a compacted storage configuration for launch of the spacecraft, and scalable to hundreds of meters in length. The boom assembly should also be readily deployable into an extended configuration upon the spacecraft reaching a desired trajectory and have sufficient strength and stiffness to maintain spacecraft components in a desired deployed configuration.